History, Humans, & the Price of Expansion How long have humans been impacting biodiversity?
-
Upload
crystal-kelley -
Category
Documents
-
view
214 -
download
0
Transcript of History, Humans, & the Price of Expansion How long have humans been impacting biodiversity?
![Page 1: History, Humans, & the Price of Expansion How long have humans been impacting biodiversity?](https://reader036.fdocuments.us/reader036/viewer/2022083009/5697bffb1a28abf838cc0e23/html5/thumbnails/1.jpg)
History, Humans, & the Price of Expansion
How long have humans been impacting biodiversity?
![Page 2: History, Humans, & the Price of Expansion How long have humans been impacting biodiversity?](https://reader036.fdocuments.us/reader036/viewer/2022083009/5697bffb1a28abf838cc0e23/html5/thumbnails/2.jpg)
Is there evidence that humans have caused extinctions in the past?
• What kind of evidence would you need to address this question?
![Page 3: History, Humans, & the Price of Expansion How long have humans been impacting biodiversity?](https://reader036.fdocuments.us/reader036/viewer/2022083009/5697bffb1a28abf838cc0e23/html5/thumbnails/3.jpg)
Catastrophic large-animal extinctions occurred around the world not long after humans first arrived in a geographical region, in the wake of initial human colonization. Numbers indicate percentages of extinct genera during the past 100,000 years. (http://www.pbs.org/wgbh/nova/stoneage/megafauna.html )
![Page 4: History, Humans, & the Price of Expansion How long have humans been impacting biodiversity?](https://reader036.fdocuments.us/reader036/viewer/2022083009/5697bffb1a28abf838cc0e23/html5/thumbnails/4.jpg)
The extinction of large mammals and flightless birds coincided closely with the arrival of humans in North America, Madagascar, and New Zealand, and less decisively earlier in Australia. In Africa, where humans and animals evolved together for millions of years, the damage was less severe.
Wilson p. 252
![Page 5: History, Humans, & the Price of Expansion How long have humans been impacting biodiversity?](https://reader036.fdocuments.us/reader036/viewer/2022083009/5697bffb1a28abf838cc0e23/html5/thumbnails/5.jpg)
Human-caused extinctions in history
• Australia – 86% of genera extinct
• North & South America - ~75% of genera extinct
• Madagascar & New Zealand – 13 species of flightless birds lost
• Hawaii – 39+ species of birds alone lost
• Africa….??
![Page 6: History, Humans, & the Price of Expansion How long have humans been impacting biodiversity?](https://reader036.fdocuments.us/reader036/viewer/2022083009/5697bffb1a28abf838cc0e23/html5/thumbnails/6.jpg)
What were the probable causes of these pre-historic extinctions?
• Over-hunting: humans as a new predator
OVERHUNTING: American bison skull heap. There were as few as 750 bison in 1890 due to overhunting. (http://en.wikinews.org/wiki/Largest_mass_extinction_in_65_million_years_underway,_scientists_say)
![Page 7: History, Humans, & the Price of Expansion How long have humans been impacting biodiversity?](https://reader036.fdocuments.us/reader036/viewer/2022083009/5697bffb1a28abf838cc0e23/html5/thumbnails/7.jpg)
What were the probable causes of these pre-historic extinctions?
• Introduction of exotic species: new competitors & predators
A severe waterlettuce (Pistia stratiotes L.) infestation on Lake Okeechobee in southern Florida.
:
![Page 8: History, Humans, & the Price of Expansion How long have humans been impacting biodiversity?](https://reader036.fdocuments.us/reader036/viewer/2022083009/5697bffb1a28abf838cc0e23/html5/thumbnails/8.jpg)
Case in Point: North America at the end of the Pleistocene
Woolly MammothSource: http://www.pbs.org/wgbh/nova/stoneage/megafauna.html
![Page 9: History, Humans, & the Price of Expansion How long have humans been impacting biodiversity?](https://reader036.fdocuments.us/reader036/viewer/2022083009/5697bffb1a28abf838cc0e23/html5/thumbnails/9.jpg)
…mega-fauna that went extinct
Giant Ground Sloth
Dire Wolf
![Page 10: History, Humans, & the Price of Expansion How long have humans been impacting biodiversity?](https://reader036.fdocuments.us/reader036/viewer/2022083009/5697bffb1a28abf838cc0e23/html5/thumbnails/10.jpg)
What caused these extinctions?
Human Hunting?
• Visit: http://www.museum.state.il.us/exhibits/larson/lp_extinction.html
A Change in Climate?
• What evidence would you need to support or refute either claim?